The objective is a simple analytical system for the accurate estimation of blood alcohol concentration using saliva as the sample. The system will be comprised of the following: 1) a strip of filter paper designed to collect an accurate volume of saliva, 2) a disposable reaction vessel containing stabilized alcohol dehydrogenase and other reagents which provide a colored end product in proportion to the alcohol concentration of the saliva, and 3) a small colorimeter designed to automatically mix sample and reagents, measure the rate of color formation, and calculate and print out the alcohol concentration of the saliva. Determination of blood alcohol by breath analysis is subject to many potential errors. The concentration of alcohol in saliva accurately reflects the blood concentration and the enzyme, alcohol dehydrogenase, is specific for alcohol. The system would be used in the determination of treatment compliance, in hospital emergency rooms and by law enforcement officers. It is anticipated that the ultimate system will be simple, small and inexpensive enough to be used in the field by inexperienced operators.